1. Field of the Invention
The invention relates to an apparatus for forming a sequencer link for a sequencer controlled by a microprogram, and a method for forming the sequencer link.
2. Description of the Prior Art
For example, an integrated high-performance DMA controller ADMA (advanced direct memory access) has four channels which are independent of each other and accomplish data transfer between media (memories, peripheral equipment) or, speaking more generally, between data sources and data sinks.
The main control of the channels is performed by microprograms, the microcommand sequence of which is controlled by a sequencer. The mode of operation of a sequencer is to provide a branching address if a test is fulfilled or a "continue" address (linear case) if a test is not fulfilled, in dependence on corresponding control information and states to be tested.
In view of the complex and time-critical tasks of the ADMA, the sequence control (control of the microcommand sequence) depends on a multiplicity of parameters, so that different control functions provided with different priorities are necessary in order to form a microaddress link. It has heretofore not been possible to provide high-power control functions, flexibility, light loading and testability of a module.